I think the new ones, Cryptum and Primordium will tie in with the game somehow. They are about the forerunner, mainly two key figures of the forerunner. I keep telling myself to get them at the library, but I never do.
Read Glasslands. It basically picks up where Halo 3 left off, with that memorial scene thrown in about half way, just to give you an idea of what timeline it uses.
As for the universe itself, one has to simply read the Wiki to see that the creators of the series have put a lot of effort into the thing. The games do not do justice to what they've created story-wise IMO.
I really think that Halo Wars, ODST, and Reach were bungies get rich quick scheme. I'm pretty sure bungie wanted to be done after halo 3, so when people decided to leave they made those three to get a whole bunch of money for new employees and projects. So I think Halo 4 will be much different than the last two games.
For what it's worth though, ODST was one of my favorite games.
Who are you?
and I play games all the time both modern & old and have played pretty much every shooter known to man, so I know what i am talking about.
"I know nothing except for the fact of my own ignorance."

As for The Tallest, it's best to ignore him. He seems to drift into various threads, say he hates everything that's ever existed, then drift back out after he's done his trolling so it's best if he's just ignored so that this thread doesn't get locked like previous ones.